Periodontitis differs from gingivitis in that it involves destruction of PDL and bone.

• A. Gingivitis involves destruction of PDL
• B. Periodontitis involves destruction of PDL and bone
• C. They are unrelated
• D. Gingivitis involves bone loss

Answer: (B)

The key idea is distinguishing tissue destruction patterns between gingival inflammation and disease that affects the tooth-supporting structures. Gingivitis is inflammation confined to the gingiva with no loss of the periodontal attachment or bone—the periodontal ligament stays intact and there is no bone resorption. Periodontitis, on the other hand, involves damage to the tissues that support the tooth, including destruction of the periodontal ligament and the alveolar bone, leading to clinical attachment loss, pocket formation, and potential tooth mobility. Because periodontitis meaningfully shifts from just inflamed gingiva to attacking the supporting structures, stating that it involves destruction of both the PDL and bone best captures the fundamental difference.